Stockholders' Equity (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common Stock, Par or Stated Value Per Share (in Dollars per share)	$ 0.0005	$ 0.0005
Treasury Stock, Shares, Acquired (in Shares)		2,148,434
Treasury Stock, Value, Acquired, Cost Method		$ 75,200,000
Stock Repurchase Program, Authorized Amount	500,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	210,200,000
Payments for Repurchase of Common Stock	$ 111,304,000	$ 211,986,000	$ 99,820,000